Mims, Hyperion, see, Dion, Thetis-new findings

Last article in the series of articles summarizing the discoveries of the Cassini spacecraft in the Saturn system. This time we are dealing with several moons of scientific importance

discussion

Dion is a moon with a diameter of 1123 km and a density of 1.41 g/cm1. The mass of the nucleus is probably 3/13 of the mass of the moon and there is probably a lot of water (29) and based on his photographs an atlas was produced (8). The moon is crushed and the side facing Saturn is crushed more than the other side. The moon has 100 craters with a diameter of over 350 km. Among these, one moon is very large, 4 km in diameter. 4 of these craters are on the side facing Saturn and 175 on the other side. Aeneas crater has a diameter of 3 km, its depth is 5 km and the height of the bulge in its center is 3 km (5). In photo 30, most of the craters have a dark bottom and light sides, and inside the large crater in the photo, 07748 km in diameter, you can see long and narrow grooves, tens of meters wide, evidence of tectonic activity (60). Also in photo 31PIA the craters have light sides and a dark bottom (07638).

The moon has a very large number of malls. These are malls on the order of hundreds of kilometers and tens of kilometers wide. Due to their dimensions, they can be regarded as shopping malls on a global scale. Some of the canyons are within craters, some cross craters and others are cut by craters which can give an indication as to when they occurred. In photo 06162PIA on the left side of a long mall there is a series of parallel, short and narrow malls 33). in photography jpg00041264N You see the sides of white canyons and the side cut by one of them has a dark side (34).

Mims

small moon Its diameter is 398 km and in terms of its size it is close to that of Enceladus. Like the other moons of Saturn, it also has many craters. It has one large crater, named Herschel, with a diameter of 139 km. There are a few shopping malls in Limassol (1). Some of the sides of the Herschel Crater are 6 km high and you can see that there were rockslides in them, a phenomenon that was also distinguished in other craters, those with a diameter of more than 15 km. Some of these landslides also have craters, which can give an indication of their age. A kind of stratigraphic section. The moon only has 7 malls. One at the northern end of Herschel Crater and the other in the southern hemisphere. These are short craters, some of them are a little more than 100 km long and a little more than 1 km deep (2). A temperature of 200°C was measured on this moon (3). The moon's low density of 1.17 g/cm4 indicates that it has a lot of water. This fact together with its close proximity to Saturn (closer than Enceladus) and its eccentric orbit should lead to tidal heat being created in it similar to Enceladus and no activity similar to the water geysers of Enceladus was found. The explanation is that the surface froze a long time ago (10). Its equatorial diameter is 5% larger than the polar diameter due to its rapid movement (XNUMX).

Hyperion

The elongated shape of the moon and its many sharp corners indicate that it broke off from a larger body. A moon that may have once belonged to Saturn and which has disintegrated for whatever reason, or was once an asteroid that was captured by Saturn's gravity. Its dimensions are 107 X 130 X 160 km. First measurements showed that its density is 60% of the volume of solid water ice, raising the possibility that 40% of its volume is empty space. The low density of the moon raises the possibility that the moon is made mainly of water ice (6). It is therefore reasonable to assume that this moon has many caves.

Hyperion has many craters, the largest of which has a diameter of 130 km. The combination between the moon's low density and its tiny gravitational force meant that meteors that hit it in the past and that created these craters, at the time of the impact, more compressed the material inside than dug into the body of the moon and most of the material that was blown no longer returned to the surface, but was blown into space (7). It is these factors that cause the spongy appearance of the moon (8).

From the many photographs broadcast to Israel, it appears that large parts of it, including craters, are covered with a light material at the bottom. It is estimated that they are a product of the downward deterioration of rocks from the upper edges of the craters to their bottoms and sublimation of the ice gave them the light shade (9). Based on a study of a dark area and a crater with a diameter of 200 meters, they came to the conclusion that the thickness of the dark material is tens of meters and below it is a light material (10). This dark matter also has an effect on the moon's spongy appearance. It is estimated that a process called thermal erosion occurs on the moon. This is a process in which the dark material accumulated at the bottom of craters is heated by sunlight, melts into the ground and the surrounding ice evaporates as a result (11).

The surface of the moon is made of a mixture of frozen water ice and organic dust. CO2 ice is also found. The brightest surface has a crystalline structure similar to that found on Earth. The CO2 is not in a pure state, but bound in a way that is not clear to other molecules (12).

See

The diameter of the moon is 1529 km and its density is 1.33 g/cm1. The moon has a lot of water and a hard rocky core that has 3/13 of its mass. The moon is a strong reflector of light. One of the most crushing of Saturn's moons. Unlike the moon Dion, its side facing Saturn is more crushed than its other side (XNUMX).

A striking and unique phenomenon of its kind on Ra is a very bright spot, from the sides of which rays emerge, a phenomenon that many like it are found on the Earth's moon and on Mercury. This spot is a crater from which bright material erupted to the sides in time after its formation (14). A wide and dark strip was also distinguished (15). in a jpg photo. 0091024N0 find a bright and flowing ground. It seems that lava flowed in this area in the past. Small and particularly dark areas were also found (16). See 7 large craters. The Tirawa crater which is 360 km in diameter and in some places 5 km deep (17) and next to it is a smaller crater which shows signs of weathering. in the photo. jpg0075319N0 Apparently the remains of an extremely large crater with a diameter of 590 km are visible. Inside it is a crater with a diameter of 236 km and next to it is a crater with a diameter of 337 km (18). Another crater with an elliptical shape and dimensions 91 X 115 km (19). In the southern hemisphere, on the side hidden from Saturn, there is a crater, the Izanagi crater, and its diameter is about 220 km (20).

On See there is evidence of tectonic activity, albeit on a relatively limited scale. Near the crater with a diameter of 50 km, the topography is soft and was probably formed during its formation (21). In another crater with a diameter of 48 km, the ground has gone through a process of wrinkling and on one of the sides there is a rockslide (22, 23). In other craters part of the ground has sunk, a phenomenon that has parallels on the Earth's moon and Mercury (24).

See a small number of malls. One narrow mall, tens of meters wide, decreases from a high area to a low area (25). The low area may have sunk and the canyon formed later. The wall of one of the craters is broken and a canyon about 100 km long emerges from it (26).

To the surprise of the researchers, it turned out that he saw a ring thousands of kilometers wide and it is inhabited by fragments and particles of material from the size of gravel to rocks. In addition, there is also a dust cloud with a width of 5900 km. One of the explanations for this phenomenon is that these materials are remnants of a collision between Ra and an asteroid or comet (27). The side facing Saturn is brighter than the other side. It is estimated that E ring particles originating from Enceladus prefer to hit this side of the moon (28).

will fly

Tethys is a moon with a diameter of 1066 km and a density of 1.21 g/cm13 (35). Its dimensions are similar to a discussion. An atlas was also built for him (8). On its surface there are 100 craters whose diameter is greater than 445 km. The largest among them, Odysseus, was 3 km in diameter. 5 craters are on the side facing Saturn and 07535 on the other side of the moon. In photo 36PIA ( 37). You see a weathered crater. The bottom of many craters is covered with light material, unlike Hyperion, whose bottom is covered with dark material (38). It is not clear what the origin of this material is. It is possible that the meteorite that created this crater penetrated the lunar crust and exposed bright material. Another possibility is that the texture of the bottom of the craters is different from that of the sides (00040104). in the photo. jpg39N You can see craters that are close to each other, their bottoms are bright and inside them are rock falls (250). In the Melathius crater, which is 40 km in diameter, there is no bulge in the center, but a chain of mountains (XNUMX).

Unlike Dion Lethits, there are only a few shopping malls. The grand canyon, Ithaca Chasma is a canyon on a global scale. It extends from pole to pole. It is over 2000 km long, 100 km wide and 2 km deep (4). It is believed that this canyon was formed when the lunar crust heated up and was under great pressure. The heating was followed by an increased cooling that froze the ocean and then the canyon was formed. It seems that in the past Thetis' course was influenced by Dion and became more eccentric. The result, tidal forces that resulted in frictional heat inside the moon, but at a certain point the orbital interaction between the two moons was broken and Tetis entered a shorter and less eccentric orbit around Saturn. At this point the moon began to cool. The freezing of the ocean created greater pressures in the crust to the point of creating the canyon. According to estimates, this ocean is at a depth of 41 km (100). In photo 42PIA you see a narrow and long canyon, tens of kilometers long and tens of meters wide (07736). The photographs of the North Pole are not sharp enough, but the impression one gets is that here too there are several canyons, although very short, tens of kilometers long (43).

In Dion and Bethys, a stream of particles moving from the ground into space was discovered, which raises the possibility of some geological activity, possibly volcanic (44). Tetis has a dark horizontal band parallel to the equator (45).

Sources

1.PIA01117: The Mimas atlas

http://photojournal.jpl.nasa.gov/catalog/PIA01117

2.PIA06256: A world of hurt

http://photojournal.jpl.nasa.gov/catalog/P06256

3. Adam D.-"Saturn's moon is the double of Star Wars Space Station" 15.2.2005

http://www.guardian.co.uk/space/article/0,14493,1414923, 00html

4. Moons-mimas

http://saturn.jpl.nasa.gov/science/moons/moonDetailscfm?pageID=9

5.PIA07534: Not quite round

http://photojournal.jpl.nasa.gov/catalog/PIA07534

6.PIA06243: Encountering Heperion (Movie)

http://photojournal.jpl.nasa.gov/catalog/PIA06243

7.PIA09728: Chiseled away

http://photojournal.jpl.nasa.gov/catalog/PIA09728

8."Cassini scientists wring out details on spongy heperion" 4.7.2007

http://http://spaceflightnow.com/cassini/070704hyperion.html

9.PIA06244: Pop-up moon

http://photojournal.jpl.nasa.gov/catalog/PIA06244

10.PIA07741: Hyperion's unusual craters

http://photojournal.jpl.nasa.gov/catalog/PIA07441

11.PIA07761: Cosmic blasting zone

http://photojournal.jpl.nasa.gov/catalog/PIA07761

12. "NASA finds hydrocarbons on Saturn's moon Hyperion" 4.7.2007

http://http://spaceflightnow.com/cassini/070704 hydrocarbons.html

13.”Cassini at Saturn Interactive Explorer (cassini) Saturn's Moons

http://saturn.jpl.nasa.gov/multimedia/CASSIE/dsp_cassinimoonsactiom.cfm

14. Rhea's great white splat 17.5.2005

http://spacedaily.com/news/cassini_05zza.html

15.PIA06630: Dark patch

http://photojournal.jpl.nasa.gov/catalog/PIA06630

16. Full-Res: N00091024.jpg

http://saturn.jpl.nasa.gov/multimedia/images/raw/raw-images-details.cfm?feImageID=124898

17.PIA07575:Tirawa at twilight

http://photojournal.jpl.nasa.gov/catalog/PIA07575

18. Full-Res: N00075319.jpg

http://saturn.jpl.nasa.gov/multimedia/images/raw/raw-images-details.cfm?feImageID=96550

19.PIA07566: Rhea: polar view

http://photojournal.jpl.nasa.gov/catalog/PIA07566

20. Morrison D. – voyagers to Saturn NASA SP-451 1982 227 p.

21.PIA07264: Catch the crater

http://photojournal.jpl.nasa.gov/catalog/PIA07264

22. Full-Res: N00091049.jpg

http://saturn.jpl.nasa.gov/multimedia/images/raw/raw-images-details.cfm?feImageID=124923

23.PIA08402: Rhea's pop-up crater

http://photojournal.jpl.nasa.gov/catalog/PIA08402

24. Rhea flying raw preview# 10

http//ciclops.org/view.php?id=1690

25. Full-Res: N00090798.jpg

http://saturn.jpl.nasa.gov/multimedia/images/raw/raw-images-details.cfm?feImageID=12671

26 Full-Res: N00114701.jpg

http://saturn.jpl.nasa.gov/multimedia/images/raw/raw-images-details.cfm?feImageID=16787

27. "Saturn moon Rhea may also have rings" 7.3.2008

http://www.saturndaily.com/reports/ Saturn_ Moon_ Rhea_ May_ Also_ Have _Rings_999.html

28.PIA11143: Darkness falls on Rhea

http://photojournal.jpl.nasa.gov/catalog/PIA11143

29.PIA08418: The Dione atlas

http://photojournal.jpl.nasa.gov/catalog/PIA08418

30.PIA06561: Aeneas on the edge

http://photojournal.jpl.nasa.gov/catalog/PIA06561

31.PIA07748: In the groove

http://photojournal.jpl.nasa.gov/catalog/PIA07748

32.PIA07638: At Carthage Linea

http://photojournal.jpl.nasa.gov/catalog/PIA07638

33.PIA06162:Dione's surprise

http://photojournal.jpl.nasa.gov/catalog/PIA06162

34. http://saturn.jpl.nasa.gov/multimedia/images/raw/casJPGFullS15/N00041264.jpg

35.PIA11008: The Thetys atlas

http://photojournal.jpl.nasa, gov/catalog/PIA11008

36.PIA07535: Icy scars

http://photojournal.jpl.nasa, gov/catalog/PIA07535

37.PIA07734: Steep scraps

http://photojournal.jpl.nasa, gov/catalog/PIA07734

38.PIA07738: Tethys in full view

http://photojournal.jpl.nasa, gov/catalog/PIA07738

39.http://saturn.jpl.nasa.gov/multimedia/images/raw/casJPBrowseS14/N00040104.jpg

40.PIA07622: Big bangs on the Tethys

http://photojournal.jpl.nasa, gov/catalog/PIA07622

41.PIA06583: The great rift

http://photojournal.jpl.nasa, gov/catalog/PIA06583

42. Rincon P.-"Saturn moon once had ocean" 14.3.2008

http://newa.bbc.co.uk/2/hi/science/nature/7297408.stm

43.PIA07736: “Hi-res” on Tethys

http://photojournal.jpl.nasa, gov/catalog/PIA07736

44. "Cassini finds moons are active" 15.6.2007

Http://www.saturndaily.com/reports/ Cassini_ Finds_ Moons_ Are _Active_999.html

45.PIA07571: with the band

http://photojournal.jpl.nasa, gov/catalog/PIA07571